Take consultation for Proper Treatment.

Consult any ayurveda physician you wl get benefit definitely avoid self medication

Hi :-Give him/her half albendazole tablet once in a month :- liv 52 syrup one tea spoon tds( after breakfast lunch and dinner) :- gasex  syrup one table spoon tds ( after breakfast ,lunch ,dinner)( himalaya company) :-add beatroot in his / her diet :- do not give tea .

Get deworming done every six months . Don't give junk foods like biscuits, cream biscuits, wafers, lays, kurkure etc. These foods cause reduced appetite and gives bloating. They fill the stomach but dont give any nutrition and by eating that their stomach gets filled and they don't eat food in sufficiently Give liv 52 syrup 5ml twice half an hour before food morning and night Also you can administer swarnaprashana drops once in a month on pushya nakshatra

you can give ayurvedic liver syrup to improve appetite of child as well as you can give swarnaprashan which will help in improving digestion.

Bmi is

Consult ayurveda physician for proper diagnosis and root cause